This invention relates to the field of piping and in particular this invention relates to equipment, sometimes designated as drain traps, for permitting the passage of fluid from one space to another.
More particularly, this invention relates to apparatus for permitting the passage of fluids from a space being continuously evacuated. Such a continuously evacuated space may be the unit area of a typical commercial air conditioning system and the apparatus of the present invention is disclosed in this context.
One of the problems facing those dealing with spaces being continuously evacuated wherein there is a tendency for the build up of fluids is the problem relating to removing the fluid from the space. Such a problem is found in the cooling coil area of typical commercial air conditioning units wherein the area is being continuously evacuated by the operation of the main air supply fan and the operation of the cooling coils causes condensation of water within the air stream.
The condensate formed on the cooling coils tends to be entrained in the air passing through the cooling coils and unless removed is passed from the unit area into the ductwork distribution system wherein it frequently occurs that the water will collect in ductwork and cause problems within the ductwork or more undesirably the water will leak from the ductwork causing damage to the interior spaces of the building being serviced.
Cooling coils have been provided with condensate pans in the bottom which are designed to collect condensate running downwardly by gravity effect across the cooling coil. Further, attempts have been made to eliminate any condensate which is carried off by the air by providing eliminators on the discharge side of the cooling coils which, by the provision of a maze-like air path, are intended to cause the disposition of entrained air on the surfaces of the eliminators and thereafter their gravity flow downwardly into the condensate pan which serves the cooling coils.
As will be recognized by those skilled in these arts, however, eliminators are not extremely efficient moisture removal devices and the known structures for permitting drainage of condensate from the condensate pans have been ineffective. The results of the ineffective drainage of fluid from the condensate pans have been that water build up occurs within the pan and reentrainment of the condensed water occurs thereby causing water carrying air to be passed into the ductwork distribution system.
It has been found in studies relating to the development of the present invention that a principal reason for the build up of water within condensate pans in known apparatus is that known trap type devices are ineffective to permit the passage of the condensate from the pan into a drain line. More specifically, it has been found that typical P traps and the like do not maintain their seal thereby permitting the passage of air from the atmosphere through the drain line and into the continuously evacuated unit casing. The passage of air into the unit casing through the condensate pan drain line is of such a magnitude as to preclude the passage of condensate in sufficient amounts out of the condensate pan and into the drainage system. Further, it has been found that the passage of air through the drain system has been sufficient to assist in the reentrainment of water otherwise condensed and collected in the condensate drain pan thus adding to the problem rather than eliminating it.